In servicing instrumentation for the measurement, control, etc., of process variables, personnel of relatively modest skills and attainments are entrusted with such servicing tasks as calibration, maintenance, troubleshooting and repair of electronic circuitry in said instrumentation.
In the prior art, simple input/output board function checks allow easy service at the board level, provided, however, that repairs, adjustments, etc., are confined to merely replacing entire misbehaving, maladjusted, or inoperative circuit boards. But such service is costly and, we have found, nevertheless requires a degree of skill sufficient for more ambitions tasks such as troubleshooting and repair on the component level, as by finding and replacing defective parts and calibrating by adjusting circuit elements.
Also known to the prior art are templates, overlays, etc. which can be fixed temporarily or permanently to circuit boards, and have thereon graphic illustration of circuitry: verbal instructions and legends, parts symbols, numbers, pictures, values, operating parameters, etc., with or without depictions of circuit interconnections; and/or other information relating to servicing or operation of the circuitry in question. While this avoids the cost of the circuit-board replacement approach to service, such template approaches as we are aware of are not suitable for servicing complex electronic circuitry such as process instrumentation, because the level of skill, at which the present invention is aimed, needs more than templates and test instruments, in order to do the job of servicing reliably and efficiently.